The present disclosure generally relates to coatings of stainless steel objects. In particular, this disclosure relates to designed alumina-based coatings formed on surfaces of medical-grade stainless steel objects.
Stainless steel (also known as inox or “inoxydable” steel) is a steel alloy which may have a minimum of 10.5% chromium content by mass. Stainless steel may not readily corrode, rust or stain with exposure to water or other fluids, and may incorporate metallic elements (other than iron (Fe)) including, but not limited to, chromium (Cr), nickel (Ni), and molybdenum (Mo), which may be useful in increasing the steel's resistance to corrosion. Various grades and surface finishes of stainless steel may be used in particular environments that an alloy may endure. Stainless steel may be used in applications where both the mechanical/structural properties of steel and resistance to corrosion are useful.
“Medical grade” or “surgical” stainless steel may be informal terms which may refer to certain grades of stainless steel that may be used in biomedical applications. Common types of stainless steels referred to as “medical grade” may include austenitic 316, 316L and 316LVM. 316, 316L and 316LVM steels may be chromium, nickel and molybdenum alloys of steel that exhibit relatively high strength and corrosion resistance and may be a common material choice for biomedical implants and equipment that are put under pressure. For example, bone fixation screws, prostheses and body piercing jewelry may be formed from austenitic 316L and 316LVM steel. 316 steel may also be used in the manufacture and handling of food and pharmaceutical products, where it may be often required to minimize metallic contamination.
Aluminum oxide, commonly known as “alumina”, is a chemical compound of aluminum and oxygen with the chemical formula AL2O3. It is the most commonly occurring of several aluminum oxides, and specifically identified as aluminum (III) oxide. Alumina may be a ceramic, crystalline material having a high hardness and a high melting point. Alumina may possess properties which may be useful in biomedical applications and dental implants, such as being bio-inert (having low chemical reactivity with bodily tissues and fluids) and mechanical properties such as relatively high stability, hardness, and resistance to wear.